OA21514: IST1516I DOES NOT REFLECT CORRECT VALUE FOR EE RTP CONNECTION NETWORK

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• A customer has an XCA EE connection network  between 2 LPARs.
  For the Enterprise Extender connection network the virtual node
  name, type, and all TG characteristics are defined on the
  corresponding GROUP definition statement instead of on the PORT
  definition statement. 1000MB was defined for the CAPACITY. When
  the RTP PU is displayed it shows a value 200 KBITS/SEC. This
  value is derived from taking 5% of the coded value. 200
  KBITS/SEC is 5% of the default value of 4M. In this case a value
  of 1000M was coded which should equal a value in the IST1516I
  of 50M. The default is being taken instead of the coded
  value and a value of 200 KBITS is displayed in the IST1516I
  when you display the RTP PU.
  

Local fix

• Code these values on the PORT statement instead of the GROUP.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All with Enterprise Extender (EE) connection *
  *                 network.                                     *
  ****************************************************************
  * PROBLEM DESCRIPTION: Incorrect initial data traffic rate     *
  *                      and allowed data traffic rate seen in   *
  *                      MSGIST1516I and MSGIST1477I when the    *
  *                      HPR PU is initially displayed for an    *
  *                      RTP pipe across a connection network.   *
  *                                                              *
  *                      If the initial data traffic rate is     *
  *                      much lower than the connection can      *
  *                      support, the performance of data        *
  *                      traffic can be impacted until data      *
  *                      traffic is ramped up to the optimal     *
  *                      rate by the HPR adaptive rate-based     *
  *                      congestion control algorithm, ARB or    *
  *                      ARB2.                                   *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  With the HPR adaptive rate-based congestion control algorithms,
  ARB and ARB2, the CAPACITY value assigned to a PU determines the
  initial data traffic rate across a TG. With ARB the initial rate
  is 10% of CAPACITY, and with ARB2 the initial rate is 5% of
  CAPACITY. From that starting point, the algorithm ramps up the
  data traffic rate until it reaches the optimal speed for the
  connection.
  
  In an EE XCA major node, a connection network can be defined on
  the PORT or on the GROUP definition statement and there can be
  multiple connection networks defined in one EE XCA major node.
  All TG characteristics, including CAPACITY, are specified on the
  PORT or GROUP definition statement where the connection network
  is defined. This is the CAPACITY value that should be used to
  determine the initial data traffic rate for traffic across the
  connection network.
  
  However, when the initial data traffic rate is being assigned
  for a connection network defined on a GROUP, the wrong CAPACITY
  value is being used. If there is another connection network
  defined on the PORT, the CAPACITY associated with the PORT is
  used, otherwise the default CAPACITY of 4M is used. This can
  result in poor performance of initial data traffic, especially
  across a high speed connection.
  
  In addition, it was found in testing that the allowed data
  traffic rate (displayed in IST1477I) on the passive side of an
  HPR pipe is initially set incorrectly for ARB2. This value
  is set to 10% of the CAPACITY value. This is correct for ARB,
  but should be 5% of the CAPACITY value for ARB2.
  

Problem conclusion

• Module ISTRCCRB has been changed to use the CAPACITY value
  specified on the EE XCA GROUP statement, for a connection
  network defined on that GROUP, to set the initial and allowed
  data rates for a connection using that connection network.
  
  Module ISTRCPTL has been changed to initially set the allowed
  data traffic rate to 5% of CAPACITY if the congestion algorithm
  is ARB2. It will still be set to 10% of CAPACITY if the
  congestion algorithm is ARB.
  
  This can be seen with a DISPLAY NET,ID=CNR_pu right after the
  HPR pipe comes up:
    IST1477I ALLOWED DATA FLOW RATE = 47 MBITS/SEC
    IST1516I INITIAL DATA FLOW RATE = 47 MBITS/SEC
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

  OA20394

• APAR is sysrouted TO one or more of the following:

  UA35160

Modules/Macros

• ISTRCCRB ISTRPCTL
  

Fix information

• Fixed component name

  VTAM V4 MVS/ESA

• Fixed component ID

  569511701

Applicable component levels

• R190 PSY UA35160

     UP07/07/26 P F707 Ž

Fix is available

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